U.S. patent application number 12/895842 was filed with the patent office on 2012-04-05 for cable for electrical and optical transmission.
This patent application is currently assigned to Apple Inc.. Invention is credited to Vince Duperron, Min Chul Kim.
Application Number | 20120080225 12/895842 |
Document ID | / |
Family ID | 45888817 |
Filed Date | 2012-04-05 |
United States Patent
Application |
20120080225 |
Kind Code |
A1 |
Kim; Min Chul ; et
al. |
April 5, 2012 |
CABLE FOR ELECTRICAL AND OPTICAL TRANSMISSION
Abstract
Circuits, methods, and apparatus that provide cables capable of
high-speed transmission while remaining compatible with legacy
signals. Other examples may have shielding that may be easily
manipulated during manufacturing, they may have good tensile
strength, and they may be less likely to be damaged by twisting and
bending that may occur during use.
Inventors: |
Kim; Min Chul; (Santa Clara,
CA) ; Duperron; Vince; (Cupertino, CA) |
Assignee: |
Apple Inc.
Cupertino
CA
|
Family ID: |
45888817 |
Appl. No.: |
12/895842 |
Filed: |
September 30, 2010 |
Current U.S.
Class: |
174/70R ;
264/1.28 |
Current CPC
Class: |
G02B 6/4416 20130101;
H01B 13/14 20130101; H01B 13/0016 20130101; H01B 11/1041 20130101;
G02B 6/4432 20130101; H01B 11/22 20130101; H01B 13/06 20130101;
H01B 13/02 20130101 |
Class at
Publication: |
174/70.R ;
264/1.28 |
International
Class: |
H01B 7/00 20060101
H01B007/00; G02B 6/04 20060101 G02B006/04 |
Claims
1. A cable comprising a plurality of fiber-optic cables, each
wrapped around the other; a plurality of electrical conductors; and
a shield surrounding the plurality of fiber-optic cables and the
plurality of electrical conductors.
2. The cable of claim 1 wherein the plurality of fiber-optic cables
comprises two fiber-optic cables.
3. The cable of claim 1 wherein the fiber-optic cables are
polytetrafluoroethylene (PTFE).
4. The cable of claim 1 wherein the fiber-optic cables are
glass.
5. The cable of claim 1 wherein the plurality of electrical
conductors comprises a plurality of electrical conductors for power
and a plurality of electrical conductors for data.
6. The cable of claim 1 wherein the plurality of electrical
conductors comprises four electrical conductors for power and two
electrical conductors for data.
7. The cable of claim 1 wherein the shield comprises at least two
pluralities of conductors wrapped as counter-rotating spirals.
8. The cable of claim 1 wherein the shield comprises a first
plurality of wires wrapped in a first direction at a first angle
and a second plurality of wires wrapped in a second direction.
9. The cable of claim 8 wherein the first angle is approximately 17
degrees.
10. The cable of claim 9 wherein the second plurality of wires are
wrapped at an angle that is approximately negative 17 degrees.
11. The cable of claim 1 further comprising a plurality of
reinforcing members.
12. The cable of claim 11 wherein at least one reinforcing member
is located in one of the plurality of conductors.
13. The cable of claim 11 wherein the reinforcing members are
aramid fibers.
14. A cable comprising: a plurality of conductors; a plurality of
fillers arranged among the plurality of conductors such that the
cable has approximately a rounded cross-section; a plurality of
reinforcing members; and a shield comprising at least two
pluralities of conductors wrapped as counter-rotating spirals.
15. The cable of claim 14 wherein at least one reinforcing member
is located in one of the plurality of conductors.
16. The cable of claim 15 wherein the at least one reinforcing
member is an aramid fiber.
17. The cable of claim 16 further comprising: a jacket surrounding
the shield, wherein the jacket is a halogen-free material.
18. The cable of claim 14 wherein the plurality of conductors
comprises a first plurality of power conductors and a second
plurality of data conductors.
19. A method of manufacturing a cable comprising: twisting a
plurality of fiber-optic cables around each other; twisting a
plurality of conductors around the plurality of fiber-optic cables
while preventing the plurality of fiber-optic cables from twisting;
annealing the plurality of fiber-optic cables.
20. The method of claim 19 wherein twisting the plurality of
fiber-optic cables comprises twisting two polytetrafluoroethylene
cables.
21. The method of claim 19 wherein twisting the plurality of
conductors around the plurality of fiber-optic cables comprises
planetary twisting the plurality of conductors around the plurality
of fiber-optic cables.
22. The method of claim 19 wherein annealing the plurality of
fiber-optic cables comprises extruding a jacket to cover the
plurality of conductors and the plurality of fiber-optic
cables.
23. The method of claim 19 wherein twisting a plurality of
conductors around the plurality of fiber-optic cables comprises
twisting a plurality of power conductors and twisting a plurality
of data conductors.
24. The method of claim 19 further comprising: before annealing the
plurality of fiber-optic cables, taping the plurality of conductors
and the plurality of fiber-optic cables.
Description
BACKGROUND
[0001] The amount of data transferred between electronic devices
has grown tremendously the last few years. Large amounts of audio,
video, text, and other types of data content, are now regularly
transferred among computers, media devices, such as handheld media
devices, displays, storage devices, and other types of electronic
devices. Since it is often desirable to transfer this data rapidly,
the data rates of these transfers have substantially increased.
[0002] This data is often transferred over cables. Unfortunately,
these cables may not be capable of conveying signals at these
higher data rates. But while improved cables capable of operating
at higher speeds are desirable, it is often useful to be backward
compatible with older or legacy technologies. Accordingly, it is
desirable to have cables that can operate at these higher data
rates while remaining compatible with legacy technologies.
[0003] One feature common to cables is the use of a braided shield.
This shield may be placed around one or more center conductors of
the cable. This shield is typically braided, that is, it is
typically formed of interwoven wire.
[0004] But this weave can be difficult to manipulate during cable
manufacturing. For example, during cable manufacturing, the
braiding may be pulled apart and soldered to form a ground
connection with one or more strain-reliefs, circuits, connector
pins, or other circuits or cable components. Since the braiding is
woven, it may be difficult to pull apart and solder. Accordingly,
it is desirable to have a shield that is more easily manipulated
during manufacturing.
[0005] One difficulty encountered with cables is that they may be
pulled, stretched, twisted, or bent. This may damage or break
either the cable or one or more internal conductors. Accordingly,
it is also desirable to have cables that have increased strength
and are less likely to be damaged by twisting or bending.
[0006] Thus, what is needed are circuits, methods, and apparatus
that provide cables capable of high-speed transmission while
remaining compatible with legacy signals, have shielding that may
be easily manipulated during manufacturing, have good tensile
strength, and are less likely to be damaged by twisting and bending
that may occur during use.
SUMMARY
[0007] Accordingly, embodiments of the present invention may
provide circuits, methods, and apparatus that provide cables
capable of high-speed transmission while remaining compatible with
legacy signals. Embodiments of the present invention may have
shielding that may be easily manipulated during manufacturing.
Embodiments of the present invention may have good tensile
strength, and may be less likely to be damaged by twisting and
bending that may occur during use.
[0008] An illustrative embodiment of the present invention may
provide a cable having both fiber-optic cables and electrical
conductors. The fiber-optic cables may be useful in conveying
high-speed signals that are compliant with current and newly
developing signaling standards. The electrical conductors may be
useful in conveying signals compliant with current or legacy
standards, such as USB2.
[0009] To increase cable flexibility of various embodiments of the
present invention, the fiber-optic cables may be twisted around
each other. Further, to reduce the losses incurred by this
twisting, the fiber-optic cables may be annealed. In one specific
embodiment of the present invention, this annealing may occur
during the encapsulation of the cable in a jacket. The fiber-optic
cables may be formed of glass, polytetrafluoroethylene, or other
material.
[0010] In various embodiments of the present invention, the
electrical conductors may have different diameters. For example,
the power conductors may have a large diameter to increase the
conductor's current-carrying capability. Data or signal conductors
may have a smaller diameter to limit the cross talk and
capacitance.
[0011] Another illustrative embodiment of the present invention may
include and arrange conductors and other materials such that the
cable has a relatively rounded cross section. This may help limit
damage that may occur due to bending and twisting of the cable.
Specifically, embodiments of the present invention may include
additional conductors. For example, additional power conductors may
be included. In other embodiments of the present invention, fillers
or other fibers may be included. These may be formed of cotton,
aramid, or other materials.
[0012] Another illustrative embodiment of the present invention may
include reinforcing members for strength. For example, the aramid
fillers mentioned above may be used to provide a rounded cross
section as well as increased strength. These or other fibers may
also be used in the electrical conductors.
[0013] Another illustrative embodiment of the present invention may
use multiple counter-rotating spirals as a shield in place of a
conventional braid. This may provide increased flexibility and may
be easily manipulated during cable manufacturing.
[0014] Various embodiments of the present invention may incorporate
one or more of these and the other features described herein. A
better understanding of the nature and advantages of the present
invention may be gained by reference to the following detailed
description and the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] FIG. 1 illustrates various layers of a high-speed cable
according to an embodiment of the present invention;
[0016] FIG. 2 illustrates a cross-section of a cable according to
an embodiment of the present invention;
[0017] FIG. 3 illustrates a side view of a portion of the cable
according to an embodiment of the present invention;
[0018] FIG. 4 illustrates a cross-section of a cable according to
an embodiment of the present invention;
[0019] FIG. 5 illustrates a detailed view of fiber optic cables
that may be employed by cables according to an embodiment of the
present invention;
[0020] FIG. 6 illustrates a side view of two fiber-optic cables
wrapped around each other; and
[0021] FIG. 7 illustrates a method of manufacturing a cable
according to an embodiment of the present invention.
DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS
[0022] FIG. 1 illustrates various layers of a high-speed cable
according to an embodiment of the present invention. This cable
includes center conductors 110, dielectric 120, shield 130, and
jacket 140. Center conductors 110 may include single conductors,
coaxial conductors, or pairs of conductors, such as twinaxial,
twisted-pair, shielded twisted pair, or other pairs of conductors.
The conductors may convey power, data, status or other information.
The conductors may be single wires or multiple strands of wires. In
some embodiments of the present invention, one or more conductors
may be formed of a group of strands of wires, where each wire is
coated with a layer of material to provide spatial separation among
the strands. This separation aids in limiting skin effects and thus
limits skin effects. This layer of material may be enamel or other
material. The wires may be arranged as a Litz wire. Each of these
various conductors may be formed of copper, aluminum, or other
conductive material. They may be coated or plated with a layer to
protect the wire from oxidation, for example, they may be plated
with silver.
[0023] Dielectric 120 may be included to isolate shield 130 from
center conductors 110. Selection of a low-loss tangent dielectric
120 may increase isolation and reduce capacitance coupling effects
between center conductors 110 and shield 130 as compared to a
lower-quality, higher-loss tangent dielectric.
[0024] Shield 130 may provide a ground path through the cable.
Shield 130 may also provide electrical isolation (or RF shielding
or isolation) for the center conductors 110. This isolation may
protect the center conductors 110 from receiving noise and spurious
signals, and the isolation may protect other lines or circuits from
noise and spurious signals generated on the center conductors 110.
Jacket 140 may be used to insulate shield 130, to provide
mechanical support, and to provide a tactile surface for users to
manipulate.
[0025] Again, embodiments of the present invention may provide
improved cables. These cables may include reinforcing members for
improved strength. They may include conductors for power and data
transmission. They may employ fibers or other filler material such
that the cable has an approximately rounded cross-section. The
cables may also be shielded in a manner that provides for easy
manipulation during manufacturing. An example is shown in the
following figure.
[0026] FIG. 2 illustrates a cross-section of a cable according to
an embodiment of the present invention. This cable may include data
conductors 210, power conductors 220, reinforcing members (shown
here as aramid fibers) 230, and filler 240. Conductors 210 and 220,
aramid fibers 230, and filler 240, may be wrapped in Mylar layer
250. Counter-rotating spirals may provide a shield 260, which may
be encapsulated by jacket 270.
[0027] Data connectors 210 may be insulated by insulating layers
212. Conductors 210 may be relatively narrow to reduce capacitance
from the conductor 210 to the other connectors 210 and 220, shield
260, as well as external conductors.
[0028] Power conductors 220 may be insulated by insulating layers
222. Connectors 220 may be relatively wide to handle relatively
large amounts of current.
[0029] Reinforcing members 230 may also be included to provide
increased cable strength. Again, in this example, the reinforcing
members are aramid fibers 230. Aramid fibers 230 may be located
inside one or more of conductors 210 and 220. Aramid fibers 230 may
also be located between or around conductors 210 and 220. In this
specific example, one of aramid fibers 230 may be located between
conductors 210 and 220.
[0030] It may be desirable that these cables have a relatively
rounded cross section. This rounded shape may improve cable
flexibility and reliability. Accordingly, a number of fillers 240
may be used. These fillers may be polytetrafluoroethylene, cotton,
or they may be formed of other types of material.
[0031] Connectors 210 and 220, fibers 230, and filler 240, may be
wrapped in Mylar layer 250. Mylar layer 250 may keep the bundle of
individual conductors, fibers, and filler together during
manufacturing.
[0032] Again, it may be desirable to provide a shield to isolate
conductors 210 and 220 from external noise sources, as well as to
prevent noise and spurious signals on conductors 210 and 220 from
radiating away from the cable. It may also be desirable to have a
shield that is easily manipulated during manufacturing. For
example, each end of these cables may be connected to a connector
plug during manufacturing. As part of this connection, the shield
may be soldered to a portion of one or more of these connector
plugs. Accordingly, it may be desirable that the shield be easily
handled such that it may be connected in this way.
[0033] Accordingly, various embodiments of the present invention
employ wires in counter-rotating spirals, such as counter-rotating
spirals 260. Counter-rotating spirals may comprise two layers of
wires wrapped in opposing directions. By having the wires wrapped
in this way, as opposed to a conventional braiding, wires in the
shield may be easily manipulated during manufacturing. That is, the
wires may be easily unwound from around the inside conductors.
While various embodiments of the present invention utilize these
counter-rotating spirals, other embodiments of the present
invention may employ conventional braiding or other shielding
techniques.
[0034] Jacket 270 may be extruded around the cable for mechanical
support and handling by a user.
[0035] Again, embodiments of the present invention may employ two
counter-rotating spirals as a shield. An example is shown in the
following figure.
[0036] FIG. 3 illustrates a side view of a portion of the cable
according to an embodiment of the present invention. This figure
illustrates a cable surrounded by jacket 310. Jacket 310 has been
cut away to reveal a first counter-rotating spiral 320 and a second
counter-rotating spiral 330. The first of these spirals may have an
angle approximately equal to phi 340. In a specific embodiment of
the present invention, phi may be equal to 17 degrees. In other
embodiments of the present invention, other angles may be used. The
second of these may have approximately the same relative angle,
shown here as negative phi 342 to indicate a different absolute
direction.
[0037] In this way, during manufacturing, the wires in the
counter-rotating spirals 320 and 330 may be easily peeled away,
straightened, and soldered or otherwise electrically connected to
locations in a connector plug.
[0038] Utilizing counter-rotating spirals 320 and 330 may also
improve flexibility of the cable. For example, when the cable is
twisted in a first direction, counter-rotating spiral 320 may
tighten while counter-rotating spiral 330 may loosen. The
tightening of counter-rotating spiral 320 may protect the internal
conductors. Similarly, when the cable is twisted in a second
direction, counter-rotating spiral 330 may tighten while
counter-rotating spiral 320 may loosen. The tightening of
counter-rotating spirals 330 may protect the internal
conductors.
[0039] Again, data rates for signals over these cables have been
increasing at a tremendous rate. Accordingly, improvements to these
cables may be needed to handle the higher data rates. But it is
often desirable to be able to support legacy standards.
Accordingly, embodiments of the present invention may provide
cables that are capable of these higher data rates while still
supporting legacy standards. An example is shown in the following
figure.
[0040] FIG. 4 illustrates a cross-section of a cable according to
an embodiment of the present invention. This figure may include
fiber optic cables 410, data conductors 420, power conductors 430,
shield 440, Mylar layer 450, and jacket 460.
[0041] Fiber-optic cables 410 are capable of handling very high
data rates. In this example, two fiber-optic cables may be included
for full duplex communication. In other embodiments of the present
invention, one cable, or more than two cables, may be included.
These fiber-optic cables may be glass, polytetrafluoroethylene, or
other material. In a various embodiments of the present invention,
these fiber-optic cables may be used to convey signals that are
consistent with standardized or proprietary signaling schemes that
have been developed, are currently being developed, or will be
developed in the future.
[0042] While fiber-optic cables 410 are capable of handling high
data rates, many current electronic devices communicate over
electrical conductors. For example, USB1 and USB2 devices
communicate using electrical conductors. Accordingly, embodiments
of the present invention also include electrical conductors for
conveying signals according to legacy standards, such as USB1 and
USB2.
[0043] Accordingly, this specific example includes electrical
conductors 420. As before, electrical conductors 420 may be
relatively narrow to reduce parasitic capacitances. These
electrical conductors may be isolated by insulation layers 422.
Power conductors 430 may be relatively wide to increase current
handling capabilities. Power conductors 430 may be insulated by
isolation layers 432. Electrical conductors 420 and 430 may be
single wires, or multiple strands of wires. In some embodiments of
the present invention, one or more conductors may be formed of a
group of strands of wires, where each wire is coated with a layer
of material to provide spatial separation among the strands. This
separation aids in limiting skin effects and thus limits skin
effects. This layer of material may be enamel or other material.
The wires may be arranged as a Litz wire. Each of these various
conductors may be formed of copper, aluminum, or other conductive
material. They may be coated or plated with a layer to protect the
wire from oxidation, for example, they may be plated with
silver.
[0044] As before, Mylar layer 440 may be used to hold the
conductors and fiber-optic cables together during manufacturing.
Fillers and fibers (not shown), such as aramid fibers, may be used
to provide a rounded cross section and reinforcement. For example,
the aramid or other types of fibers may be included around, among,
or inside the various cables and conductors of embodiments of the
present invention.
[0045] Shield 450 may be used to isolate conductors 420 and 430.
This shielding may be formed using conventional techniques, such as
braiding. In other embodiments of the present invention,
counter-rotating spirals may be used, as shown above. Jacket 460
may be extruded around the cable for mechanical support and
handling by a user.
[0046] FIG. 5 illustrates a detailed view of fiber optic cables 510
that may be employed by cables according to an embodiment of the
present invention. Cables 510 may be mechanically supported by
filler 520. Fiber-optic cables 510 and fillers 520 may be wrapped
by Mylar film 530 for mechanical support during manufacturing.
[0047] Fiber optic cables 510 may be wrapped around each other.
This may improve flexibility of the overall cable. For example, if
fiber-optic cables 510 are parallel to each other throughout the
cable, when the cable is bent, a fiber-optic cable inside the
bending radius may experience a compression force, while a
fiber-optic cable outside the bending radius may experience an
expansion force. These differential forces may damage the cable. By
twisting or wrapping the cables around each other, these
compression and expansion forces may be distributed along the
length of the cable, thereby improving cable reliability. An
example is shown in the following figure.
[0048] FIG. 6 illustrates a side view of fiber-optic cables 610 and
620 wrapped around each other. As fiber-optic cables 610 and 620
are bent, compression and expansion forces are distributed along
the length of the fiber-optic cables, thereby improving overall
cable flexibility and reliability.
[0049] Unfortunately, twisting fiber-optic cables in this way can
increase their loss significantly. Accordingly, embodiments of the
present invention anneal these fiber-optic cables after twisting to
reduce this loss. In a specific embodiment of the present
invention, this annealing occurs during jacket extrusion. An
example is shown in the following figure.
[0050] FIG. 7 illustrates a method of manufacturing a cable
according to an embodiment of the present invention. A number of
spools 710 may provide power and data conductors 720 and
fiber-optic cables 730 for a cable. Power and data conductors 720
and fiber-optic cables 730 may be bound together by taping 740.
Jacket extrusion 750 may extrude a jacket over the cable for
mechanical support and manipulation by a user.
[0051] In this embodiment of the present invention, fiber-optic
cables 730 may be held in place, that is, they are not twisted, as
the cable is assembled. Power and data conductors 720 may be
twisted around two fiber-optic cables 730. This may prevent further
losses in fiber-optic cables 730.
[0052] Again, embodiments of the present invention may employ
annealing to reduce losses in fiber-optic cables 730 due to their
being twisted together, as shown in FIG. 6. In a specific
embodiment of the present invention, this annealing is achieved
during jacket extrusion 750.
[0053] Specifically, the jacket may be a halogen-free material. Due
to the properties of halogen-free materials, the jacket may be
extruded at a slower rate than would otherwise be necessary for a
material that includes halogens. Also, in various embodiments of
the present invention, the temperature at jacket extrusion 750 may
be higher than would otherwise be necessary. This slower rate and
possibly higher temperature provides for annealing of fiber-optic
cables 730.
[0054] The losses incurred by twisting fiber-optic cables 730 may
be increased if excessive tension is placed on fiber-optic cables
730 during construction of the cable. Accordingly, various
embodiments of the present invention may reduce the tension placed
on fiber-optic cables 730 during construction. A specific
embodiment of the present invention may maintain no more tension on
the fiber-optic cables 730 than is necessary for the construction
of the cable.
[0055] The above description of embodiments of the invention has
been presented for the purposes of illustration and description. It
is not intended to be exhaustive or to limit the invention to the
precise form described, and many modifications and variations are
possible in light of the teaching above. The embodiments were
chosen and described in order to best explain the principles of the
invention and its practical applications to thereby enable others
skilled in the art to best utilize the invention in various
embodiments and with various modifications as are suited to the
particular use contemplated. Thus, it will be appreciated that the
invention is intended to cover all modifications and equivalents
within the scope of the following claims.
* * * * *